Slab-debarker having blade carrying members biased to engage the sides of the slab



Dec. 15, 1959 w. R. STREED 2,917,090

SLAB-DEBARKER HAVING BLADE CARRYING MEMBERS BIASED T0 ENGAGE THE SIDES OF THE SLAB Filed Jan. 22, 1959 4 Sheets-Sheet 1 flffo rneys Dec. 15, 1959 w. R. STREED 2,917,090

SLAB-DEBARKER HAVING BLADE CARRYING MEMBERS BIASED T0 ENGAGE THE SIDES OF THE SLAB Filed Jan. 22, 1959 4 Sheets-Sheet 2 INVENTOR. \fvillidm R Si'reed yw' ws v Afforne ys W. R. STREED Dec. .15, 1959 SLAB-DEBARKER HAVING BLADE CARRYING MEMBERS BIASED T0 ENGAGE THE SIDES OF THE SLAB 4 sheets-sheet :5

Filed Jan. 22. 1959 WWII/[11m mu E.

5 INVENTOR.

William R Sfreed 1959 w. R. STREED 2,917,090

SLAB-DEBARKER HAVING BLADE CARRYING MEMBERS BIASED T0 ENGAGE THE SIDES OF THE SLAB Filed Jan. 22, 1959 4 Sheets-Sheet 4 @wdH UH m INVENTOR. l Vfllllim i? SIreed BYM ,mz, fl yuw.

Af/brneys United States Patent SLAB-DEBARKER HAVING BLADE CARRYING MEMBERS BIASED TO ENGAGE THE SIDES 0F TI-E SLAB William R. Streed, Gadsden, Ala, assignor to Clyde C.

Harris and William R. Streed, doing business as Machine Products Company Application January 22, 1959, Serial No. 788,437

11 Claims. (Cl. 144-208) This invention relates to debarking apparatus and more particularly to slab debarking apparatus having a debarking head mounted for sliding axial movement along a shaft, and being urged continuously along the shaft into cutting relation with a slab.

Heretofore, it has been difficult to remove bark directly adjacent knots, limbs, and other protuberances on a slab or the like, as upon contact with the protuberance, the entire debarking head is moved out of contact with the slab and thereby leaves an area in which bark is not removed. Thus, the prior art debarkers have not been entirely satisfactory in debarking slabs having numerous protuberances thereon.

The present invention comprises a rotary debarking head that is continuously urged simultaneously in two directions into cutting relation with a slab being can veyed beneath the debarking head. The debarking head is continuously urged downwardly in a vertical direction into debarking engagement with the slab passing therebeneath. The other direction is in an axial direction along the shaft on which the debarking head is mounted for rotation with blade cvarrying members mounted on each side of the slab and being urged into debarking engagement with the sides of the slab passing therebeneath. Upon a knot or protuberance on the side of the slab striking a blade carrying member, the blade carrying member on that side of the slab is moved axially of the shaft away from the slab while the blade carrying member on the other side of the slab is not moved or affected in any way by this movement, and remains in its original debarking position. Upon passage of the aforesaid one blade carrying member over the knot, it moves toward the slab again. It is evident that an improved bark removing apparatus is obtained by having blade carrying members mounted on each side of a slab for individual axial movement on a shaft with the blade carrying members being urged downwardly and laterally into debarking relation with a slab being conveyed therebeneath.

My apparatus may be used effectively on logs and other members having bark thereon. As used in the specification and claims herein, the term slab will be interpreted to include logs and other similar members from which bark is to be removed.

Apparatus illustrating features of my invention is shown in the accompanying drawings fo'rminga part of this application, in which:

Fig. 1 is a side elevational view of the preferred embodiment of my debarking apparatus and showing slabs being conveyed under a plurality of debarking heads;

Fig. 2 is an elevational view looking generally along the line 22 of Fig. 1;

Fig. 3 is an enlarged elevational view of the debarking head initially contacting the slab in the debarking apparatus shown in Fig. 1 and showing the debarking head removed from the debarking apparatus;

Fig. 4 is an enlarged elevational view of the second debarking head of my debarking apparatus shown in Fig.

2,917,090 Patented Dec. 15, 1959 l which contacts the slab after the first debarking head and is shown removed from the debarking apparatus;

Fig. 5 is an enlarged elevational view of the third debarking head removed from the debarking apparatus;

Fig. 6 is an enlarged sectional view taken through the axis of rotation of the second debarking head shown in Fig. 4, and showing the debarking head mounted for sliding axial movement along the rotary shaft;

Fig. 7 is an enlarged fragmentary elevational view of several links of the link chain that convey the slabs through the debarking apparatus under the debarking heads;

Fig. 8 is a side elevational view of a modification of my invention in which the blade carrying members of the second and third debarking heads are mounted on separate horizontal axes for relative vertical movement;

Fig. 9 is a plan view looking generally along line 9--9 of Fig. 8 and showing the blade carrying members of the third debarking head mounted on separate axes;

Fig. 10 is a fragmental front elevational View of another modification of my invention; and,

Fig. 11 is a fragmental front elevational view showing a further modified form of my invention.

Referring now in detail to the drawings and more particularly to Figs. 1 and 2, I show debarking apparatus having slabs S supported on a pair of angles 10 and being conveyed therealong by a chain indicated generally by the numeral 12. A motor 13 is provided to drive chain 12 through a drive shaft 14 having a pulley 15 mounted thereon. A pulley 17 is mounted on a countershaft 18 and drives the chain 12. As shown in Fig. l, 15 by pulley belt 19. A sprocket 21 is fixed to countershaft 18 and drives the chaine 12. As shown in Fig. 1, an idler sprocket 21a is mounted adjacent the opposite end of the angles 10 from the sprocket 21 for engaging and supporting that end of the chain 12.

A conveyor belt 22 is provided beneath-chain 12 to receive bark and the like from slabs S, and conveys the bark to an end of the debarking apparatus where it can be easily removed. Conveyor belt 22 is mounted on end rollers 23. Shaft 24 of one end roller 23 is driven by a pulley belt 26 extending between suitable pulleys on the drive shaft 14 and roller shaft 24. Thus, motor 13 drives both chain 12 and conveyor belt 22.

Referring now to Fig. 7, links 28 and 29 of chain 12 are shown in enlarged detail. Links 29 have forwardly facing teeth 31 on the upper side thereof which engage the underside of slabs S and thereby move slabs S longitudinally of the debarking apparatus along the angles 10. Links 28 have rearwardly facing teeth 32 thereon which prevent slabs S from moving forwardly of the chain 12 when the debarking operation begins. Thus, teeth 31 and 32 secure the slabs S on chain 12 and prevent any relative lonngitudinal movement between chain 12 and slabs S.

A plurality of debarking heads is mounted on the debarking apparatus over the slabs S and contact the slabs S in bark cutting relation as slabs S move under the debarking heads. The debarking head that initially contacts the slabs S is designated generally by the numeral 33. The second or intermediate debarking head which contacts slab S after the debarking head 33 .is designated by the numeral 34, and the third or last debarking head is designated generally by the numeral 36. Each of the debarking heads 33, 34, and 36 is driven in a similar manner as follows: A motor 37 is mounted on a platform 38 secured to the main frame of my debarking apparatus and has a drive shaft 39 extending therefrom. As shown in Fig. 2, a pulley 41 is mounted on drive shaft 39 and drives a pulley 42 through a pair of pulley belts 43. Each of the debarking heads 33, 34 and 36 is suspended by a pair of arms 46 mounted on a shaft 47 which in turn is freely mounted on side plates 48 of the main frame of my debarking apparatus and is in axial align ment with the drive shaft 39. The lower ends of the arms 46 have bearings 49 secured thereto in which is mounted a shaft 51 to which pulley 42 is secured.

Debarking heads 33, 34 and 36 are continuously urged downwardly in cutting engagement with the slabs S passing therebencath. For this purpose, one end of a crank arm 53 is secured to the shaft 47. The other end of the crank arm 53 is secured to a piston rod 54 of a hydraulic cylinder 56. The hydraulic cylinder 56 is secured to one of the side plates 48. Thus, upon actuation of the hydraulic cylinders 56, the debarking heads 33, 34 and 36 will be continuously urged downwardly into debarking engagement with the slabs S passing therebeneath. The amount of pressure exerted by the hydraulic cylinders 56 is determined by a suitable control valve, whereby the downward pressure of the debarking head may be varied.

The first debarking head 33 that initially contacts the slabs in debarking relation is shown removed from the debarking apparatus in Fig. 3, and comprises a pair of parallel, circular plates 57 that are secured to the shaft 51. Radially extending cutter blades 58 are positioned between and secured to the plates 57. The blades 58 slope inwardly toward shaft 51 from end plates 57 to form a gradually sloping cutting edge 59 that faces outwardly from shaft 51. The blades 58 are angularly spaced about the shaft 51 thus presenting a plurality of cutting edges about the circumference of debarking head 33. The cutting head 33 is used primarily to remove knots and other protuberances from the surface of the slab.

The second or intermediate debarking head 34 is shown in Fig. 4 detached from the debarking apparatus and the third or last debarking head '36 is shown in Fig. detached from the debarking apparatus. The debarking heads 34 and 36 are both mounted for sliding axial movement along the shafts 51 on which they are mounted. Thus, the second and third debarking heads 34 and 36 are different from the first debarking head 33 in that debarking head 33 is not mounted for axial sliding movement along shaft 51. The debarking heads 34 and 36 are identical to each other in structure except for the cutter blades, the cutter blades on debarking head 34 being of a greater slope than the cutter blades on debarking head 36. For the purposes of illustration, only the debarking head 34 will be described in detail.

As shown in Fig. 6, debarking head 34 comprises a pair of oppositely arranged blade carrying members 61, each of which is adapted for sliding axial movement along the shaft 51. Each of the blade carrying members 61 comprises a circular end plate member 62 secured to a sleeve 63. Secured to the sleeve 63 is an inner cylindrical slide 64 having an abutment face 65 on the outer face thereof. An outer annular slide 66 is secured to the outer end of each of the sleeves 63 and has an inwardly facing abutment face 67 thereon. A key 68 is secured to opposite slides of the slide 66 and fits in a keyway 69 on shaft 51. A key 71 is fixed to opposite sides of shaft 51 and suitable keyways are provided in the cylindrical slides 64 for engaging the keys 71. The slides 64 and 66 thus may move axially of the shaft 51 along the keys 71 and the keyway 69, respectively. A stop member 72 is secured to shaft 51 by an internally threaded nut 73 which engages threads on shaft 51, as shown. A leather cup-like member 74 is positioned between the stop 72 and nut 73 on shaft 51 and forms an outer circumferential surface, along which the sleeve 63 may slide as well as acting to absorb shock from abutment faces 65 contacting stop 72 in the outward extended position of each of the blade carrying members 61.

Relatively long radially extending cutter blades 76 and relatively short radially extending cutter blades 77 are alternately secured to each sleeve 63, whereby the long blades 76 on one sleeve 63 are axially aligned with the short cutter blades 77 on the other opposite sleeve 63. Thus, as noted in Fig. 6, the long cutter blades 76 on opposed blade carrying members 61 overlap each other, and even in the full extended position, there is a slight overlap between the long cutter blades 76 on the oppositely disposed plate carrying members 61. The blades 76 slope inwardly gradually directly adjacent the plate member 62 and thereafter slope inwardly at a sharp angle to form a relatively deep pocket on the outer circumference of the debarking head 34 between the plate members 61 so that a slab S may be received therein. Cutting edges 78 are formed on the outer edges of the blades 76 and 77 and contact the slabs S in cutting relation. The cutting edges 78 face outwardly from the shaft 51, and the relatively deep sloping portion of the slab receiving pocket is adapted to remove bark from the sides of the slab S.

The blade carrying members 61 are continuously urged toward each other along the shaft 51 by fluid pressure. An axially extending opening 81 is provided adjacent each end of the shaft 51 and a port 32 leads therefrom to the space defined between the slide 64 and stop 72. A rotary valve 83 is mounted on shaft 51 and allows shaft 51 to rotate relative thereto. A supply line 84 for fluid under pressure, such as air, leads to rotary valve 8 3 through a regulator valve 86 which may be set to a predetermined pressure to maintain the air pressure within the rotary valve 83 constant. Fluid under pressure is supplied to the rotary valve 83 at the opposite side of the debarker head by a supply conduit 85 which communicates with regulator valve 86. A check valve 87 is provided in supply conduit 85 adjacent rotary valve 83 and prevents air from flowing from supply line 85 to the supply line 84 when there is an excess of pressure in line 85. A relief valve 89 is provided in supply conduit adjacent each regulating valve 86, as shown in Fig. 6, to prevent excess pressure from building up in the supply line 85. Upon a sudden movement of slide 64 to extended position, which causes a sudden exit of air from the air space adjacent slide 64, the relief valve 89 will be opened to exhaust the air to atmosphere immediately upon being forced from the air space around shaft 51. Thus, a constant inward pressure is maintained against the blade carrying members 61 at all times.

As shown in Fig. 6, the blade carrying members 61 are in the full inward position with the abutting face 67 on outer slide 66 in engagement with the nut 73 thereby limiting inward movement of the blade carrying members 61. Upon contact of the blades 76 and 77 with a slab S, the blade carrying members 61 will be pushed outwardly by the slab against the constant air pressure in the air space between the slide 64 and stop 72 whereby the cutting edges 78 assume positions which correspond to the general contour of the slab being debarked. In the outer or extended position of a blade carrying member 61, the abutting face 65 engages stop 72 and thereby limits outward movement of the blade carrying members 61. Upon movement of the blade carrying members 61 the slides 64 move on the keys 71 and the keys 68 move along the keyways 69 on shaft 51. The shaft 51 is continually rotating, and a continuous downward pressure is exerted through the cylinder 56 and crank arm 53. Thus, the blade carrying members 61 are simultaneously urged axially of the shaft 51 by air pressure and urged vertically downwardly by the cylinders 56.

The third or last debarking head 36 to engage the slabs S is formed of a relatively shallow contour whereby it is adapted to receive wider slabs or slabs from larger logs. That is, the debarking head 34 is adapted to engage the entire upper or curved surface of a relatively narrow slab while the debarking head 36 is adapted to engage the entire upper or curved surface of a wide slab. Accordingly, by providing both heads 34- and 36, the apparatus is adapted for receiving slabs of various widths and sizes. As pointed out previously, the only difference between debarking head 36 and debarking head 34 which has just been described is the difference in contour or slope of the blade members. Thus, identical reference numerals are applied to debarking head 36 except for the blades.

Debarking head 36 comprises relatively long radially extending blades 91 and short blades 92. The blades 91 and 92 slope inwardly gradually in a substantially uniform manner from the end plates 62 of the blade carrying members 61. A cutting edge 93 is formed on the edge of each of the blades 91 and 92 and faces outwardly from the shaft 51. The long blades 91 on opposed blade carrying members 61 overlap each other and the short blades 92 on one blade carrying member 61 are arranged in axial alignment with the long blades 91 on the other opposed blade carrying member 61. A gradual uniform sloping of the outer cutting edges 93 of blades 91 and 92 forms a slab receiving pocket that generally fits the contour of relatively large slabs S passing beneath the debarking head 36. The debarking head 33 normally removes the knots and other protuberances from the slabs S and the second debarking head 34 removes the bark from the relatively narrow slabs and from the sides of the wider slab S passing through the apparatus. Thus, when a narrow slab S reaches the third debarking head 36, practically all of the protuberances and bark have been removed therefrom and debarking head 36 smoothes the outer surface of the slab and removes any adhering material which has not been removed by the other two debarking heads 33 and 34. Accordingly the debarking head 36 not only removes bark from the wider slabs but also aids in the removal of bark from the smaller slabs. A pivotally mounted roller 96 is mounted behind debarking head 36 and holds the slabs S down on the angles until the slabs are removed from my debarking apparatus.

Referring now to Figs. 8 and 9, a modification of my invention is shown in which the blade carrying members of the second and third debarking head are mounted on separate shafts. The first debarking head 33 is identical to that in the preferred embodiment of the invention and has identical reference numerals. The second debarking head is indicated generally by the numeral 99 and the third debarking head by the numeral 100. Heads 99 and 100 are identical except for the cutter blades and comprise a blade carrying member 101 mounted on shaft 102 and a blade carrying member 103 mounted on shaft 104. Shaft 102 is supported by arms 106 and is driven by a pulley belt 107 extending between motor 108 and pulley 109 on shaft 102. The arms 106 are urged downwardly by cylinder 111 through piston rod 112 which is secured to a crank arm 113 that is fixed to the shaft 114. Shaft 114 is aligned axially with the drive shaft cylinder 121 and crank arm 122 secured to shaft 118. I

Thus, it is evident that blade carrying member 101 may move vertically without any corresponding movement of blade carrying member 103 and if blade carrying member 101 engages a projection on the upper side of slab S which raises blade carrying member 101, the blade carrying member 103 will not move and will remain in engagement with the slab S. The blade carrying members 101 and 103 are shown somewhat diagrammatically in Fig. 9, it being understood that the blade carrying members shown in Fig. 9 are urged by air pressure inwardly on shafts 102 and 104, respectively, as in the preferred embodiment of the invention shown in detail in 6 Fig. 6 for debarking head 34. The only difference between the debarking heads 99 and shown in Fig. 8 is in the slope of the blades as in the preferred embodiment of the invention. Debarking head 99 has blades of a greater slope than the debarking head 100.

From the foregoing, it will be seen that I have devised an improved debarking head which comprises a blade carrying member mounted over a slab passing therebeneath with the blade carrying member being urged along the shaft on which it is mounted .into cutting engagement with the slab. At the same time, the blade carrying member is urged vertically downwardly into cutting engagement with the slab S. This arrangement allows a blade carrying member adjacent one side of the slab to be moved along the shaft while not affecting the operation of the blade carrying member on the other side of the slab in any manner. My debarking apparatus has been found to be most effective in removing both knots and the bark around knots and other protuberances on slabs and the like.

In Fig. 10 of the drawings, I show another modified form of my invention in which blade carrying members 123 and 124 are mounted for axial movement along a shaft 126. That is, the blade carrying members 123 and 124 are keyed to the shaft 126 whereby they rotate with the shaft but are adapted for axial movement relative thereto. Projecting outwardly from the blade carrying members 123 and 124 are bearing sleeve members 127 and 128 having annular grooves 129 and 131 therein, respectively. The blade carrying members 123 and 124 are urged inwardly by L-shaped arms 132 and 133 which engage the annular recesses 129 and 131, as shown. The ends of the L-shaped arms 132 and 13 3 opposite the annular grooves 129 and 131 are operatively connected to pistons 134 and 136 which are mounted for sliding movement within a cylinder 137. Fluid under pressure, such as air, is introduced into the cylinder 137 between the pistons 134 and 136 by a conduit 138. The pressure at which the fluid is introduced between the pistons 134 and 136 is controlled by suitable means, well known in the art, whereby the desired pressure is exerted.

In Fig. 11 of the drawings, I show a further modified form of my invention which comprises a pair of blade carrying members 139 and 141 which are mounted for axial movement on a shaft 142. That is, the blade carrying members 139 and 141 are keyed to the shaft 142 whereby they rotate with the shaft but are adapted for axial movement relative thereto. Mounted on the shaft 142 in axially spaced relationship to the outer ends of the blade carrying members 139 and 141 are spring abutment members 143 and 144, respectively. Surrounding the shaft 142 between the spring abutment 143 and the adjacent end of the blade carrying member 139 is a compression spring 146 and surrounding the shaft 142 between the spring abutment 144 and the adjacent end of the blade carrying member 141 is a compression spring 147. The compression springs 146 and 147 urge the blade carrying members 139 and 141 toward each other whereby a constant pressure is applied against the slab being debarked.

While I have shown my invention in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is: i

1. A debarking head adapted to engage in cutting re lation a slab being conveyed therebeneath, comprising a horizontal shaft, a blade carrying member mounted for rotation with said shaft and adapted to extend over the slab, said blade carrying member being mounted for axial sliding movement along said shaft and adapted to engage the slab, a plurality of angularly' spaced blades mounted on said blade-carrying member and sloping toward the shaft from the blade carrying member to form a curved cutting edge facing outwardly from the shaft, means continuously urging said blade carrying member axially along the shaft into cutting engagement with the slab, and means continuously urging the blade carrying member vertically downwardly into cutting engagement with the slab simultaneously with the means urging the blade carrying member axially along the shaft.

2. A debarking head adapted to engage in cutting relation a slab being conveyed therebeneath, comprising a horizontally extending shaft, means to rotate said shaft, a pair of spaced blade carrying members mounted on said shaft for rotation therewith, one of said members being mounted on said shaft for axial sliding movement therealong toward and away from the other member, means for continuously urging the slidable blade carrying member toward the other blade carrying member, a plurality of angularly spaced cutter blades mounted on each of said blade carrying members and extending between the blade carrying members in position to overlie a slab to be debarked, at least some of the blades on one blade carrying member overlapping at least some of the blades on the other blade carrying member, and each of the blades sloping inwardly toward the shaft from the blade carrying member to which it is secured to form a curved cutting edge facing outwardly from the shaft whereby a slab receiving pocket is formed by the cutter blades on the outer circumference of the debarking head between the blade carrying members.

3. A debarking head adapted to engage in cutting relation a slab being conveyed therebeneath, comprising a blade carrying member mounted on a substantially hori zontal shaft for rotation therewith, said member being mounted on said shaft for axial sliding movement therealong, a plurality of angularly spaced blades mounted on said blade carrying member and extending therefrom in position to overlie a slab to be debarked, each of the blades sloping toward the shaft from the blade carrying member to form a curved cutting edge facing outwardly from the shaft, and means continuously urging said blade carrying member along the shaft into cutting engagement with the slab passing beneath the debarking head.

4. A debarking head adapted to engage in cutting relation a slab being conveyed therebeneath, comprising a horizontally extending shaft, means to rotate said shaft, a pair of spaced blade carrying members mounted on said shaft for rotation therewith, at least one of said blade carrying members being mounted on said shaft for axial sliding movement therealong toward and away from the other blade carrying member, a plurality of angularly spaced cutter blades mounted on each of the blade carrying members and adapted to extend over the slab, at least some of the blades on one blade carrying member overlapping at least some of the blades on the other blade carrying member, each of the blades sloping inwardly toward the shaft from the blade carrying member to which it is secured whereby a slab receiving pocket is formed by said blades on the outer circumference of the debarking head, and means continuously urging said one blade carrying member axially along the shaft into cutting engagement with the slab passing beneath the debarking head. i

5. A downwardly urged debarking head adapted to engage in cutting relation a slab being conveyed therebeneath, comprising a horizontally extending shaft, a blade carrying member mounted on said shaft for rotation therewith, said blade carrying member being mounted on said shaft for axial sliding movement therealong, a plurality of angularly spaced blades mounted on said blade carrying member and adapted to extend over the slab in cutting relation thereto. each of the blades sloping toward the shaft from the blade carrying member to form a curved cutting edge facing outwardly from the shaft, and means continuously urging said blade carrying member along the 8 shaft to cutting engagement with the slabjpassing beneath the debarking head.

6. A downwardly urged debarking head adapted for vertical movement toward and away from a slab passing beneath said head to engage the slab in cutting relation comprising a horizontally extending shaft, a pair of spaced blade carrying members mounted on said shaft for rotation therewith and adapted to extend over the slab, each of said blade carrying members being mounted on said shaft for axial sliding movement therealong toward and away from each other and adapted to engage the slab in cutting relation, a plurality of angularly spaced blades mounted on each of said blade carrying members and sloping toward the shaft from the blade carrying members to form a curved cutting edge facing outwardly from the shaft, means continuously urging said blade carrying members axially along the shaft into cutting engagement with the slab, and means continuously urging the blade carrying members vertically downwardly into cutting engage.- ment with the slab simultaneously with the means urging the blade carrying members axially along the shaft.

7. A downwardly urged debarking head adapted for vertical movement toward and away from a slab passing beneath said head to engage the slab in cutting relation comprising a horizontally extending shaft, means to rotate said shaft, a pair of spaced blade carrying members mounted on said shaft for rotation therewith, said blade carrying members being mounted on said shaft for axial sliding movement therealong toward and away from each other, a plurality of angularly spaced cutter blades mounted on each of the blade carrying members and extending radially between the blade carrying members, at least some of the blades on one blade carrying member overlapping at least some of the blades on the other blade carrying member, each of the blades sloping inwardly toward the shaft from the blade carrying member to which it is secured whereby a slab receiving pocket is formed by said blades on the outer circumference of the debarking head, and means continuously urging the blade carrying members axially along the shaft into cutting engagement with the slab passing beneath the debarking head.

8. Debarking apparatus for debarking a slab, comprising a blade carrying member mounted on a horizontal axis and adapted to extend over a slab passing therebeneath to engage the slab in cutting relation, a second blade carrying member mounted on a horizontal axis and adapted to extend over said slab and to engage in cutting relation the other side of the slab opposite said one side, each of said blade carrying members being mounted for sliding axial movement on the horizontal axis on which it is mounted, a plurality of angularly spaced cutter blades mounted on each of said blade carrying members and ex tending generally axially of the horizontal axis on which the member is mounted, each of the blades sloping inwardly toward the horizontal axis on which the respective blade carrying members are mounted thereby forming a slab receiving pocket on the outer circumference of the blade carrying members with the slab being conveyed under the blade carrying members and engaged in cutting relation by said blades, and means continuously urging each of the blade carrying members along the horizontal axis on which each member is mounted into cutting engagement with the slab.

9. Debarking apparatus comprising means to convey a slab in the direction of its longitudinal axis, a pair of spaced debarking heads mounted for rotation on horizontal shafts over the longitudinal axis of the slab, means mounting said debarking heads for vertical movement, means continuously urging said debarking heads downwardly into cutting relation with. the slab passing therebeneath, the debarking head contacting the slab initially comprising blade members sloping inwardly from the sides of the debarking head toward the axis of rotation of the debarking head thereby forming a slab receiving pocket between said sides for the slab passing beneath the debarking head,

the second debarking head comprising a blade carrying member mounted for sliding axial movement on the horizontal shaft on which it is mounted, a plurality of angularly spaced blades mounted on said blade carrying memher and extending over the slab, each of the blades sloping toward the shaft from the blade carrying member, and means continuously urging said blade carrying member along the shaft on which it is mounted into cutting engagement with the slab passing therebeneath.

10. Debarking apparatus comprising means to convey a slab in the direction of its longitudinal axis, a first debarking head mounted for rotation on a horizontal axis and comprising blade members sloping inwardly from the sides of the debarking head toward the horizontal axis thereby forming a slab receiving pocket between the sides of the head, a second debarking head spaced from said first debarking head and adapted to contact the slab after said first head, said second head comprising a pair of spaced blade carrying members mounted on a horizontal shaft for rotation therewith, one of the blade carrying members being mounted on said shaft for axial sliding movement therealong toward and away from the other blade carrying member, means for continuously urging said slidable blade carrying member toward the other blade carrying member, a plurality of angularly spaced cutter blades mounted on each of said blade carrying members and adapted to extend over the slab, at least some of the blades on one blade carrying member overlapping at least some of the blades on the other blade carrying member, means mounting both of said heads for vertical movement toward and away from the slab passing therebeneath, and means continuously urging both of said heads downwardly into cutting relation with the slab.

11. Debarking apparatus defined in claim 10 further characterized in that the contour of the blade members on the first debarking head is diiferent from the contour of the blade members on the second debarking head. 1

References Cited in the file of this patent UNITED STATES PATENTS Pangborn June 12, 1928 1,956,653 Onstad May 1, 1934 

